Here is some information that should be useful to everyone in one way or another if not then you should have told us your secret months ago. lol
A Li-ion batteries life is on a time clock from the day it's produced and how it is used, maintained and the number of cycles it goes through reduces it's life. Even when not being used at all the clock is ticking and life is shortening.
So if any of you are like me I know many of you are far worse than me when it comes to the amount of stress put through it with flashing and extreme general use. Hopefully this will shed some light for us as to what we can do to try and prolong the life of our batteries.
The majority of the following information is from the book “Batteries in a Portable World – A Handbook on Rechargeable Batteries for Non-Engineers” (2nd edition) and Battery University™
Special thanks to the books author and sponsor of Battery University™,
Isidor Buchmann
CEO and Founder, Cadex Electronics Inc.
How to Prolong the Life of Li-ion Batteries
Battery wear-down on lithium-based batteries is caused by two activities: actual usage or cycling, and aging. The wear-down effects by usage and aging apply to all batteries but this is more pronounced on lithium-based systems.
The Li-ion batteries prefer a shallow discharge. Partial discharges produce less wear than a full discharge and the capacity loss per cycle is reduced. A periodic full discharge is not required because the lithium-based battery has no memory. A full cycle constitutes a discharge to 3V/cell. When specifying the number of cycles a lithium-based battery can endure, manufacturers commonly use an 80 percent depth of discharge. This method resembles a reasonably accurate field simulation. It also achieves a higher cycle count than doing full discharges.
Simple Guidelines
Charge the Li-ion often, except before a long storage. Avoid repeated deep discharges.
Keep the Li-ion battery cool. Prevent storage in a hot car. Never freeze a battery.
Avoid purchasing spare Li-ion batteries for later use. Observe manufacturing date when purchasing. Do not buy old stock, even if sold at clearance prices.
Hints to long battery life
3.92V/cell is the best upper voltage threshold for cobalt-based lithium-ion. Charging batteries to this voltage level has been shown to double cycle life. Lithium-ion systems for defense applications make use of the lower voltage threshold. The negative is reduced capacity.
The charge current of Li-ion should be moderate (0.5C for cobalt-based lithium-ion).The lower charge current reduces the time in which the cell resides at 4.20V. It should be noted that a 0.5C charge only adds marginally to the charge time over 1C because the topping charge will be shorter. A high current charge tends to push the voltage up and forces it into the voltage limit prematurely.
Memory Myth or Fact?
Lithium batteries are not affected by memory, but the chemistry has its own peculiarities. Current inhibiting pacifier layers affect them through plate oxidation. This degenerative effect is non-correctable on a lithium-based system
Calibration
A more serious issue is maintenance requirements, better known as capacity re-learning. This procedure is needed on a regular basis to calibrate the battery.
Why is calibration needed?
The answer is in correcting the tracking errors that occur between the battery and the digital sensing circuit during use. The most ideal battery use, as far as fuel-gauge accuracy is concerned, is a full charge followed by a full discharge at a constant 1C rate. This ensures that the tracking error is less than one percent per cycle. However, a battery may be discharged for only a few minutes at a time and commonly at a lower C-rate than 1C. Worst of all, the load may be uneven and vary drastically. Eventually, the true capacity of the battery no longer synchronizes with the fuel gauge and "a full charge and discharge are needed to ‘re-learn’ or calibrate the battery."
How often is calibration needed?
The answer lies in the type of battery application. For practical purposes, a calibration is recommended once every three months or after every 40 short cycles.
What happens if the battery is not calibrated regularly? Can such a battery be used in confidence?
Such a battery is able to function normally, but the digital readout will be inaccurate. If not corrected, the fuel gauge information simply becomes a nuisance.
Just Tell Me WTF I Should Do!
Charge your battery as often as possible, partial discharges are actually better for your battery
Once your battery is charged to 100% avoid leaving it plugged in any longer if you are not using a OEM charger.
Your battery should never get hot from charging if it does this is a sign it may be damaged.
If fuel gauge starts acting up calibrate your battery.
Yeah but how the f^$% do I calibrate my battery?
Charge phone up and then delete your battery stats.
Unplug your phone from your wall charger and let your battery drain all the way down until phone shuts off.
While still off charge phone to 100% and then boot up as normal.
There is so much more that it's mind boggling but I think this covers the main parts and beyond for everyone. So far it appears that the bump method is not necessary nor are the numerous other steps.
I can only laugh when I think that the reason the method of calibration I was using was actually working is due to the fact that the "wipe batt stats, drain battery completely and charge to 100%" is basically the last step and all that is essentially needed.
3 hours? That's it? I thought whenever I charged from empty to full when it's off it's longer.. I should time it.. hmm
darkamikaze said:
3 hours? That's it? I thought whenever I charged from empty to full when it's off it's longer.. I should time it.. hmm
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I removed the time completely since some may vary. But the 3 hours is how long it should take to charge on a standalone battery charger. So rather than confuse or have questions it's better without it.
Nice work!
Charging a 1500mAh battery at 500mAh for example will take 3 hours. The Captivate charges at 2 levels though depending on if it's USB (500mAh max for charge + phone use) or a charger (whatever it says on the charger up to ~1200mAh) so it can probably get done in under 2 hours.
The phone charges to 4.23V and stops charging when full but continues to run on external power, and shuts down at 3.500V where it only consumes current to monitor the power button.
Just for reference.
Battery Stats
Since this is the first time i had a really good battery life. I would like to share it with everyone. Please see the attached screen shots.
I am using Darky's 9.1 with SuckerPunch's 1280/500 Kernel and TLJL3 modem.
I hope this will help anyone trying to get more battery life out of their Captivate.
Thanks,
CuriousTech said:
Nice work!
Charging a 1500mAh battery at 500mAh for example will take 3 hours. The Captivate charges at 2 levels though depending on if it's USB (500mAh max for charge + phone use) or a charger (whatever it says on the charger up to ~1200mAh) so it can probably get done in under 2 hours.
The phone charges to 4.23V and stops charging when full but continues to run on external power, and shuts down at 3.500V where it only consumes current to monitor the power button.
Just for reference.
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Thanks Curious appreciate it and thanks for the additional info.
I had some other random thoughts about the calibration because I keep seeing so many posts daily.
For example "I installed a new kernel 15 minutes ago, recalibrated and the battery drain is horrible." or "After a few charges it lasted longer."
I don't think people get the idea of calibration. Recalibrating determines the capacity of the battery to convert to a % full gauge. To do that you need to fully charge until the "Battery full. Unplug charger." notification, and not rely on the display and unplugging as soon as it hits 100%. That's the inaccurate display that you're trying to calibrate.
Think of it like having an opaque container and a teaspoon. You think the container can hold 100 teaspoons, so you stop filling at 100. All you can get out of it is 100 until you try to fill until it tops off and then count how many come back out.
The phone works the same way. It has an ammeter that monitors the charge current and drain current from the battery from the time you unplug it until it shuts off and remembers that total as the capacity. Unless it's recharged in the middle which voids the data.
After that full discharge, it should stay pretty accurate even with partial discharges. At least until the next rom/kernel flash which wipes it out. At that point (I assume) it uses a simple voltage level and some relative amps drawn to display the gauge, instead of the smarter method of keeping a constant value of mAh by adding when charging and subtracting when draining to know exaclty how full the battery is.
CuriousTech said:
Nice work!
Charging a 1500mAh battery at 500mAh for example will take 3 hours. The Captivate charges at 2 levels though depending on if it's USB (500mAh max for charge + phone use) or a charger (whatever it says on the charger up to ~1200mAh) so it can probably get done in under 2 hours.
The phone charges to 4.23V and stops charging when full but continues to run on external power, and shuts down at 3.500V where it only consumes current to monitor the power button.
Just for reference.
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Click to collapse
hm. so if the phone switches to external power when the charge is full, is it okay to leave my phone plugged in once it's done charging? or is it just the fact that the battery is holding a full (4.2V) charge for a long time that's bad for its health?
in any case, useful post! i knew there were ways to preserve the life of li-ion batteries, but was never well-versed on the details.
Yes to both. Once the battery is fully charged, the charge circuit stops completely. It doesn't even need to trickle charge, so leaving it plugged in doesn't hurt anything.
Once the charge is complete the voltage isn't being held at 4.20V so it can come back down a little. I think BatteryUniversity generalizes becuase there have been many different designs over the years that weren't as good as what we have now, and some may have trickle charged their Li-Ions which shortens the life.
Which is it that wipes the battery stats, ROM or kernel? or is it both?
CuriousTech said:
Yes to both. Once the battery is fully charged, the charge circuit stops completely. It doesn't even need to trickle charge, so leaving it plugged in doesn't hurt anything.
Once the charge is complete the voltage isn't being held at 4.20V so it can come back down a little. I think BatteryUniversity generalizes becuase there have been many different designs over the years that weren't as good as what we have now, and some may have trickle charged their Li-Ions which shortens the life.
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One word of caution though is to ensure that you are using an OEM charger. Battery University recommends that you unplug once capacity is reached but perhaps this is a general statement for Li-ion batteries as you state.
zerkai said:
Which is it that wipes the battery stats, ROM or kernel? or is it both?
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Both. The first thing in a ROM flash script is to format all the partitions, so that means the batterstats.bin file is erased. When flashing a new kernel the file gets reset by some other means. No idea what. It could be CWM.
Yeah but how the f^$% do I calibrate my battery?
Charge phone up and then delete your battery stats.
Unplug your phone from your wall charger and let your battery drain all the way down until phone shuts off.
While still off charge phone to 100% and then boot up as normal.
My noob question is, how do you delete the battery stats?
iNFRiNGE said:
One word of caution though is to ensure that you are using an OEM charger. Battery University recommends that you unplug once capacity is reached but perhaps this is a general statement for Li-ion batteries as you state.
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What happens when you introduce the variable of occasional car charger use?
Sanctus Peregrinus said:
Yeah but how the f^$% do I calibrate my battery?
Charge phone up and then delete your battery stats.
Unplug your phone from your wall charger and let your battery drain all the way down until phone shuts off.
While still off charge phone to 100% and then boot up as normal.
My noob question is, how do you delete the battery stats?
Click to expand...
Click to collapse
the file is located at /data/system/batterystats.bin . you'll need a file browser with root access (i use root explorer, a paid app). make sure you mount the storage as read/write or you won't be able to delete the file.
after that, reboot your phone and it will rebuild the batterystats file.
***disclaimer: be careful doing this. if you delete a crucial file, you risk messing up or bricking your phone. such is life.
Nice write up with alot of interesting information. I have never calibrated my battery but will have to try it out. Thanks for posting.
Sent from my SAMSUNG-SGH-I897 using XDA App
I'm not positive of this, but I don't think batterystats.bin holds any battery capacity or health info. I was looking at BatteryManager and it looks like a database of processes and what they use only. But there is info somewhere that gets lost easily, which is the capacity and current amount consumed.
I've been skipping the delete of that file (using CWM) and have noticed that it recalibrates fine anyway. This coming from the point of dropping just after unplugging, which is a good indication that the info is gone.
It doesn't matter if you use a car charger, USB, or AC. The phone has the actual smart charger in it, the external connection is just the power supply. The chip inside regulates and monitors the charge.
So think of it this way. The charger knows when the battery is empty or full, and measures what goes in and comes out. So to know the capacity, it has to go from full to empty. That's really all there is to it. Just wait for the real "Battery full" before unplugging.
Hi. I noticed, that my Sensation after charging battery showing green led, that battery is full.
What I noticed on battery widget, that 100mA of tickle charge is provided to the battery even when it is fully charged what is bad for Li-ion and Li-poly cells.
I need to verify that on DVM and a scope, but it looks like I said.
So, is there any chance to edit ROM to really interrupt charging when battery hits 4.2V?
Li-ion cannot absorb overcharge, and when fully charged the charge current must be cut off. A continuous trickle charge would cause plating of metallic lithium, and this could compromise safety. To minimize stress, keep the lithium-ion battery at the 4.20V/cell peak voltage as short a time as possible.
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Source: http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
Mike
That should already happen inside the battery's controller.
Even though the system might appear as if it was still charging, the batteries are quite intelligent these days and the charging circuits are built so that the battery's lifetime is as long as possible.
When the LED goes green and the display reports 100% the battery isn't fully charged.
After some time (usually 30-60 minutes after LED goes green) then battery will be full and charging will stop.
Swyped from my HTC Sensation
I have flashed and restore my tab many times, mostly stocks recoveries, but now when i charge my tablet turned on i have noticed that when its 100% charged it shows a voltage of 4.3, also if i charge my tablet turned off and then i turn it on battery shows 95%, and takes around 15-20 minutes to get to 100 and also shows 4.3v. I have been reading about the average voltage of Li ion battery's and the recommended is 4.2v, or it battery capacity or lifespan decreases. I didnt check the voltage before so i dont know if it is normal, im using stock charger. Im afraid of overcharging the so suffered Nvidia Battery. Does anyone has 4.3 voltage at full charge?
One thing i've always wanted to know is if we plug our phones at 100% battery it still uses power from the battery and keep charging it over and over. Or if it uses power directly of the wall without consuming battery.
I want to use my phone for longer periods but im worried about battery health in the long run
fabricio7p said:
One thing i've always wanted to know is if we plug our phones at 100% battery it still uses power from the battery and keep charging it over and over. Or if it uses power directly of the wall without consuming battery.
I want to use my phone for longer periods but im worried about battery health in the long run
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The common recommendation for battery health on most smartphones with Li ion battery, is to charge often (avoid deep discharge/charge cycles), and not leave it on the charger for long periods of time when it is fully charged.
When connected to the charger and fully charged, it will let the battery drop slightly, then recharge, over and over again. I've seen the battery meter on this phone drop down from 100% to 99% when connected to the charger. Although I have a feeling it is doing this a lot more than you would be able to detect from the % meter.
redpoint73 said:
The common recommendation for battery health on most smartphones with Li ion battery, is to charge often (avoid deep discharge/charge cycles), and not leave it on the charger for long periods of time when it is fully charged.
When connected to the charger and fully charged, it will let the battery drop slightly, then recharge, over and over again. I've seen the battery meter on this phone drop down from 100% to 99% when connected to the charger. Although I have a feeling it is doing this a lot more than you would be able to detect from the % meter.
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I see, so no aparent benefit in using it with power cable conected.
thank you
fabricio7p said:
I see, so no aparent benefit in using it with power cable conected.
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In fact, more likely to be harmful than beneficial. I'd say it is better to use it for a while, let the charge drop (say down to 60-80%) than recharge to full, and disconnect the charger (don't leave it charging after it is full).
I should add that this is somewhat debatable. I don't follow all these rules myself. I'm pretty sloppy about putting the phone on the charger when I go to bed, and not unplugging it until I wake up. So plugged in for 8 hours or so, when it only takes 1-2 hours to charge to full. And we all drain the battery pretty low from time to time. So again, the is the deep discharging that should generally be avoided.
But if you want general guidelines or "best practice" than there it is.
I think its good idea to leave phone charging
If you want to charge the battery to the top end, you can charge it to 100%, let half a hour for the battery to cool and for the ions to set into some equilibrium state, and then you can charge it for a little bit more. (The battery percentage will not necessarily show it. The battery voltage is not all the time 100% correlated with its electric charge).
But as redpoint73 said, the common recommendation for Li ion battery is to disconnect it from charger while full.
Hi everyone, im having a problem with this phone:
1- Charging the phone never reach 100% in one charge, it always stops charing at a random number, for example 70%, no matter how much time i let the phone charging it never goes past that. The solution is unplug and plug again, then it reaches 100%.
2- The number 1 is not a big deal but this is. The phone automatically turn off at a random number again, let say 66%, and i cant turn it on. If i connect the phone to the charger it says 0% battery. Is not like the % freezes at 66% and i use it all day and then turn off. For example, i have the phone at 100%, i start using it and i see the % going down like normal and after an hour or two of using it suddenly turn off and im not able to turn it on again because the battery is at 0%.
I tried:
Hard reset, wiping cache, data.
Hard reset, wiping cache, data and installing the latest stock rom.
New battery.
Different charger.
I have no idea what else to try, anyone have a clue?
Thanks!
I think the battery is broken, also had the problem. Then I bought me one on Ebay for 9,99€ and now everything is good again.
Try using a -known- good cable and charger.
Make sure the port contacts are clean and debris free. Always charge with screen off.
You can also try powering the phone off and see if this alters its charging pattern.
My best guess...
When it auto shuts down again pull the battery and measure its actual voltage to determine if it's at about 6%.
If actual voltage indicates it's at 6%* may be a bad battery (limited capacity) or a hardware failure (shutting the charge cycle down prematurely).
If battery actually has 20% or higher when the phone shuts down) it indicates a hardware failure in the phone.
If battery temp exceeds about 102°F during charging the phone will abort the charge; make sure this isn't the cause. A hot charging battery in a cool room could indicate a battery or hardware failure. If battery temp exceeds 107°F or so in operation the phone may also auto shutdown.
Excessive cold (>32°F) will effect battery capacity severely.
Don't charge a cold Li battery (under 70°F).
Never charge if at or below freezing**.
Li's like a charge temp range of 80-95°F
They prefer frequent, short mid range charge cycles (40-65%) vs topping them off beyond 80%
*hunt down the voltage/% charge for this battery
**can cause Li plating which will permanently degrade the cell